Found 223 races near Boulder County, CO

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DEC
12

Windsor, CO
• 35.7 miles
$15 -$62
Santa Catch 5K, 10K and 1 Mile Kids Fun RunSaturday December 12, 2025Windsor Lake, Windsor CO Start your holiday season with the joy of running, with courses around Windsor Lake and the Canal...
1m 5K 10K
34
DEC
12

Thornton, CO
• 26.2 miles
$16 -$45
Kick off the holiday season with a spirited run/walk at Thornton's Carpenter Park. Choose from the chip-timed 5k, or experience the festive atmosphere in a shorter distance in our untimed Fun...
5K 75m
31
DEC
19

Denver, CO
• 32.1 miles
$37 -$59
 The Santa's Dash for Cash event is a celebration of Slo-Hi/Denver and EVERY finisher will get a bonus envelope! Some of the gift envelopes contain CA$H, at least one envelope includes $100! 5k...
5K
32
DEC
20

Denver, CO
• 34.6 miles
$30 -$40
Get into the holiday spirit with the Ugly Sweater 5K! Runners and walkers, young and old, are invited to join us at Washington Park in Denver for a flat, fast 5K. Dress in a tacky sweater – the...
5K
50
DEC
26

Centennial, CO
• 46.5 miles
$30 -$45
🎉 Start Your Year on the Right Foot! 🏃‍♀️🏃‍♂️Join the New Year's Run - New Beginnings Starts Today!Kick off the new year with energy, excitement, and a community of runners ready to chase their...
1m 5K 10K Half Marathon
2
DEC
31

Lyons, CO
• 9.9 miles
$10 -$50
This is a Test
12K
3
DEC
31

Fort Collins, CO
• 36.0 miles
$25 -$35
RESULTS 2025 Run out the old year, and welcome the new! One of Fort Collins’ oldest races, the Resolution Run, is back for its 42nd year! Get a head start on your New Year's Resolution by...
5K
15
JAN
1

Arvada, CO
• 25.3 miles
$34 -$54
The Resolute Runner 5K is the KICK OFF PARTY OF THE YEAR! It's time to be RESOLUTE, to retroactively earn your pumpkin pie and chocolate truffles, and to start the new year on the right foot,...
5K
28
FEB
13

Arvada, CO
• 25.4 miles
$30 -$50
Are you a Heart Throb?  Grab your best running buddy and come on out to Johnny Roberts Memorial Park just down from Olde Town Arvada.  Celebrate the ability to get your heart pumping by cruising...
5K
47
FEB
28

Highlands Ranch, CO
• 45.6 miles
$38 -$65
Winter never disappoints us when racing in February in Highlands Ranch!  You won't feel chilly after a course so hilly!  After conquering the 5k, warm up with hot apple cider or hot cocoa at the...
5K
28
MAR
13

Westminster, CO
• 21.4 miles
$38 -$58
Join us for the annual Erin Go Bragh 7.77k! This is THE LUCKIEST race on earth! There may not be a real pot of gold at the finish line of this happy-go-lucky fun run, but there WILL be UNLIMITED...
7K
23
MAR
14

Severance, CO
• 39.0 miles
$15 -$95
Celebrate the luck of the Irish at Lucky Brew! All participants will receive chip timing, photos, Lucky Brew performance shirt and a great after party, complete with beverages, food, awards for...
5K 10K 15K Half Marathon
MAR
21

Golden, CO
• 21.2 miles
$20 -$85
All-Out Multicourse is proud to host our 15th Annual Spring Fever, a rewarding event for both novice and experienced athletes set against the backdrop of Table Mountain and the stunning Colorado...
5K 10K Half Marathon
33
MAR
28

Denver, CO
• 34.6 miles
$25 -$50
Is it spring or still winter?  We'll know when we run the Central Park 5k at the end of March!  Celebrate the end of winter with us on this flat and fast course in the historic Central Park...
5K
41
APR
4

Denver, CO
• 34.6 miles
$30 -$40
The Donut Dash 5K is Denver’s race that ends with donuts. Runners and walkers can take advantage of a flat and fast course, and then enjoy fresh donuts at the finish. Our mission is to bring...
5K
36
APR
11

Littleton, CO
• 39.3 miles
$40 -$255
Welcome to the Platte River Half Marathon, Relay & 5k race, one of the most exciting and popular races in the Denver Metro Area! This race is held annually in Littleton, CO. We’re thrilled to...
5K Half Marathon
3
APR
24

Westminster, CO
• 21.7 miles
$20 -$85
Unleash your inner superhero at the 15th Annual Beat the Heat event! This year, we're calling all champions to assemble where one of Colorado's favorite trails joins one of its most glorious...
5K 10K Half Marathon
10
APR
25

Denver, CO
• 36.3 miles
$15 -$56
Ready to gallop around Denver with some friends?  Yeah, you are!  Come frolic with us at the Unicorn Runner 5k at Great Lawn Park to kick off your spring running season!  You'll earn a sweet tee...
2m 5K
4
MAY
2

Boulder, CO
• 7.2 miles
Rise Against Suicide's 17th annual Emerge 5K Walk/Run Join Rise Against Suicide's 17th annual Emerge 5K Walk/Run- a free, family-friendly walk/run supporting youth mental health and suicide...
5K
1
MAY
2

Fort Collins, CO
• 50.3 miles
$40 -$235
Early Bird Registration will open on July 1, 2026. Join us for the Colorado Marathon in Fort Collins next May! Our annual event takes place in the stunning Poudre Canyon and the gorgeous natural...
5K 10K Half Marathon Marathon
5